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Dual-homed host

(also dual-homed gateway)

Dual-homed host definition

A dual-homed host is an application-based firewall that protects trusted networks (e.g., a corporate network) from malicious traffic. It monitors all network traffic from untrusted networks (like the internet) and acts as the first line of defense, ensuring that no malicious traffic can enter. The term “dual-homed host” can be used to define any gateway, firewall, or proxy that provides secure services or applications to an untrusted network.

How a dual-homed host works

  • A dual-homed host is a firewall system with two network interfaces (NICs).
  • This system sits between an untrusted network and a trusted network to ensure secure access.
  • The dual-homed host is connected to the untrusted network (e.g., the internet) and the trusted network (e.g., internal) at the same time.
  • With a dual-homed host, IP packets are not directly routed from an untrusted network to the trusted network.
  • The systems inside the firewall and outside the firewall (on the internet) can communicate with the dual-homed host, but they can’t communicate directly with each other.